Concrete systems psychology is the study of human systems across the varied biological contexts and situations of everyday life.[5][6][7]

Contract-systems psychology

Contract-systems psychology is about the human systems actualization through participative organizations.[8]

Family systems psychology

Family systems psychology is a more general name for the subfield of family therapists. E.g. Murray Bowen, Michael E. Kerr, and Baard[9] and researchers have begun to theoretize a psychology of the family as a system.[10]

Organismic-systems psychology

Through the application of organismic-systems biology to human behavior Ludwig von Bertalanffy conceived and developed the organismic-systems psychology, as the theoretical prospect needed for the gradual comprehension of the various ways human personalities may evolve and how they could evolve properly, being supported by a holistic interpretation of human behavior.[11]

Ergonomics, also called "human factors", is the application of scientific information concerning objects, systems and environment for human use (definition adopted by the International Ergonomics Association in 2007). Ergonomics is commonly described as the way companies design tasks and work areas to maximize the efficiency and quality of their employees’ work. However, ergonomics comes into everything which involves people. Work systems, sports and leisure, health and safety should all embody ergonomics principles if well designed.[citation needed]

Equipment design is intended to maximize productivity by reducing operator fatigue and discomfort. The field is also called biotechnology, human engineering, and human factors engineering. Ergonomic research is primarily performed by ergonomists who study human capabilities in relationship to their work demands. Information derived from ergonomists contributes to the design and evaluation of tasks, jobs, products, environments and systems in order to make them compatible with the needs, abilities and limitations of people.[citation needed]

Family systems therapy, also referred to as "family therapy" and "couple and family therapy", is a branch of psychotherapy related to relationship counseling that works with families and couples in intimate relationships to nurture change and development. It tends to view the family as a system, family relationships as an important factor in psychological health. As such, family problems have been seen to arise as an emergent property of systemic interactions, rather than to be blamed on individual members. Marriage and Family Therapists (MFTs) are the most specifically trained in this type of psychotherapy.[citation needed]

Industrial and organizational psychology also known as "work psychology", "occupational psychology" or "personnel psychology" concerns the application of psychological theories, research methods, and intervention strategies to workplace issues. Industrial and organizational psychologists are interested in making organizations more productive while ensuring workers are able to lead physically and psychologically healthy lives. Relevant topics include personnel psychology, motivation and leadership, employee selection, training and development, organization development and guided change, organizational behavior, and job and family issues.[citation needed]

Perceptual control theory (PCT) is a psychological theory of animal and human behavior originated by maverick scientist William T. Powers. In contrast with other theories of psychology and behavior, which assume that behavior is a function of perception — that perceptual inputs determine or cause behavior — PCT postulates that an organism's behavior is a means of controlling its perceptions. In contrast with engineering control theory, the reference variable for each negative feedback control loop in a control hierarchy is set from within the system (the organism), rather than by an external agent changing the setpoint of the controller.[12] PCT also applies to nonliving autonomic systems.[13]

^Miller, J.G. (1971). A theoretical review of individual and group psychological reaction to stress, in Grosser G.H. The threat of impending disaster: contributions to the psychology of stress. Mit Press. ISBN0262570270.